Quality of Service (QoS) is a well-known computer networking term that describes the overall expected performance of a service, based on such characteristics as packet loss, bit rate, throughput, transmission delay, availability, jitter, etc. In the field of computer networking, specifically, QoS often refers to traffic prioritization and resource reservation control mechanisms rather than the achieved service quality. That is, QoS techniques have been configured for many years to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to various data flows.
QoS is particularly important for the transport of traffic with special requirements. For example traditional QoS has been centered on supporting applications with strict network performance requirements, such as Voice over IP (VoIP) technology and many others. Generally, to manage QoS, network customers and providers can enter into a service level agreement (SLA) which specifies guarantees for the ability of a network/protocol to give guaranteed performance/throughput/latency bounds based on mutually agreed measures, usually by prioritizing traffic. In other approaches, resources are reserved at each step on the network for the call as it is set up.
Generally, QoS and priority control has been restricted to higher-level control, such as based on network administrator configurations in conjunction with services offered on network devices (e.g., routers, switches, etc.). In particular, conventional approaches to QoS and priority have been limited to such categories as traffic type, traffic class, network-level priority (e.g., high- or low-priority queueing), and so on, and have not provided individual application stakeholders any instrument to control how their traffic could be handled differently within the network.